g0database

A SQL database, written from scratch in Go

Inspired by

• Compilers: Principles, Techniques, and Tools
• Designing Data-Intensive Applications
• How query engines work
• dolthub/go-mysql-server

Lexer

• Split raw sql command to token

raw sql: select id, name, age from user where status = 'ACTIVE' and id > 10

=> tokens: ["select", "id", ",", "name", ",", "age", "from", "user", "where", "status", "=", "'", "ACTIVE", "'", "and", "id", ">", "10"]

Parser

• Make Abstract syntax tree (AST) from list tokens

root
 |- select
 |---- fields (id, name, age)
 |- from
 |---- tables (user)
 |- where
 |---- conditions
           |---- status
           |---- =
           |---- ACTIVE
       |- AND
           |---- id
           |---- >
           |---- 10